A non-linear viscoelastic model for sediments flocculated in the presence of seawater salts

Goñi, Christian; Jeldres, Ricardo I.; Toledo, Pedro G.; Stickland, Anthony D.; Scales, Peter J.

doi:10.1016/j.colsurfa.2015.06.036

Cited by 15 publications

(7 citation statements)

References 25 publications

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“…Fixing the particle concentration of the suspension, s, at 500 kg/m 3 in this study we added 0.005-1.55 mol/L of monovalent electrolyte, sodium chloride (NaCl), into the water-kaolinite suspension to investigate the impact of electrolyte addition on the rheological properties of the suspension. This concentration range was similar to previously reported rheological experiments (Kelessidis et al 2007;Goñi et al 2015). For a comparison of monovalent, divalent and trivalent electrolytes, 0.005-1.55 mol/L of divalent electrolyte, calcium chloride (CaCl 2 ), and trivalent electrolyte, Al(NO 3 ) 3 •9H 2 O,were also added into the water-sediment suspension at a sediment concentration of 500 kg/m 3 respectively.…”

Section: Methodssupporting

confidence: 82%

“…The Dual-Bingham plastic rheological model was found to provide a satisfactory simulation of the experimental data, and for the dynamic rheological properties, empirical formulae of the elastic modulus and dynamic viscosity were obtained in term of exponential forms of sediment concentration with a high goodness of fit. Moreover, Goñi et al (2015) evaluated the rheological properties of sediments flocculated in the presence of seawater salts and proposed a non-linear viscoelastic model to describe them. This model incorporates three parameters which are correlated to physical attributes of the material and was found to be a better fit for the experimental studies over the entire range of shear loads applied.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study of the rheology of water–kaolinite suspensions

Zhu

2021

Water Supply

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How the added electrolyte condition and size of primary sediment particles, as well as the particle concentration, affect the rheological behaviours of water-sediment suspension remains to be of interest in sediment field. In this work, rheological experiments of water-kaolinite suspensions with different electrolyte conditions, two particle sizes and 39 solid concentrations were performed. The Bingham fluid model has been adopted to fit the experimental data, and the viscosity and Bingham shear stress values were calculated for each suspension. It has been found that an increase in electrolyte concentration and/or valence leads to a larger viscosity value of the suspension, whereas an increase in electrolyte valence yields a smaller Bingham shear stress value. A simple interpretation based on DLVO theory was presented in this study. It has also been observed that a fine-grained kaolinite suspension corresponds to larger suspension viscosity and Bingham shear stress values. Additionally, some experimental information on the viscosity-solid concentration and Bingham shear stress-solid concentration relationships were also presented in this study. For the viscosity-solid concentration data, the Krieger and Dougherty formula provided the best fit, and a simple exponential relation showed a good fit for the measured shear stress-solid concentration data. HIGHLIGHT This manuscript is valuable in terms of studying ow the added electrolyte condition and size of primary sediment particles, as well as the particle concentration, affect the rheological behaviours of water-sediment suspension.

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Section: Methodssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Experimental study of the rheology of water–kaolinite suspensions

Zhu

2021

Water Supply

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“…27,28 While a yield stress is most commonly associated with viscoplastic behavior, creep tests have shown that flocculated mineral suspensions exhibit a viscoelastic response to a broad range of shear stress conditions. 29,30 Furthermore, many soft sediments are also highly heterogeneous in nature 16,31 and so exhibit significant spatial variation in mechanical properties such as compressive and shear yield stress, Young's modulus and Poisson ratio. The local mechanical properties of the sediment are also influenced by the presence of gas bubbles 17,32,33 and hysteresis effects due to disturbance of the bed during bubble release.…”

Section: Introductionmentioning

confidence: 99%

“…Concentrated mineral suspensions found in mining tailings, wastewater slurries, and nuclear sludge exhibit a complex, non‐Newtonian response to stress, typified by shear thinning characteristics, a shear and compressive yield stress and sometimes thixotropic behavior . While a yield stress is most commonly associated with viscoplastic behavior, creep tests have shown that flocculated mineral suspensions exhibit a viscoelastic response to a broad range of shear stress conditions . Furthermore, many soft sediments are also highly heterogeneous in nature and so exhibit significant spatial variation in mechanical properties such as compressive and shear yield stress, Young's modulus and Poisson ratio.…”

Section: Introductionmentioning

confidence: 99%

Yield stress dependency on the evolution of bubble populations generated in consolidated soft sediments

et al. 2017

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Retention of hydrogen bubbles within consolidated soft sediments represents an important safety consideration for the management of legacy nuclear wastes due to the potential for acute gas release. Gas retention sufficiently reduced the bulk density of intermediate yield stress (<800 Pa) sediments for the bed to become buoyant with respect to an aqueous supernatant, potentially inducing Rayleigh-Taylor instabilities. X-ray computed tomography revealed that beds of 7-234 Pa yield stress retained very similar, steady state size distributions of mature bubbles, limited to 9 mm equivalent spherical diameter, for long residence times. This implied a dominant gas release mechanism dictated by the pore to millimeter scale bubble population, not previously identified in such weak sediments and unrelated to the bubbles' buoyant force. At 1112 Pa yield stress, large bubbles of up to 20 mm diameter were observed to grow through induction of lateral cracks, facilitating gas transport to the bed periphery, thereby limiting the maximum void fraction, while nonhomogeneous gas generation promoted the formation of low density regions rich with microbubbles which similarly provide pathways for gas release.

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“…On the other hand, Dishon et al [24] showed that at pH 5.5, Na + neutralizes the silica surface between 0.5 and 1 M, K + between 0.2 and 0.5 M, and Cs + at a concentration close to 0.1 M.The relationship between interactions at the colloidal scale and the macroscopic characteristics of silica suspensions is of great practical interest [25]. For example, the management of tailings (mainly quartz) in the mining industry is determined by the flow properties of the pulps and, in recent times, the presence of salts due to the boom in the use of seawater in regions with water shortages [26][27][28][29][30]. Rheology knowledge makes it possible to optimize the tailings management and defines the amount of water and energy that must be used to transport the pulps from the exit of thickeners to the tailings deposit.…”

mentioning

confidence: 99%

Analysis of Silica Pulp Viscoelasticity in Saline Media: The Effect of Cation Size

et al. 2019

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The effect of alkali metal chlorides on the viscoelastic behavior and yielding properties of silica suspensions was studied through creep-recovery and dynamic oscillatory tests with stress control. Then, the viscoelasticity of the pulps was correlated with the silica zeta potential, aggregate size, and the percentage of cations adsorbed on the surface of the ore. The results indicate that larger cations are more prone to adhere to the silica surface, which increases the number of ionic bonds that bind the particles. This generates stronger particle networks and a greater agglomeration of particles, especially those smaller than 10 µm. As the size of the bare cations increases, the rheological response provides higher values of yield stress, complex viscosity, and viscoelastic moduli, but in turn, pulps undergo minor deformations under the application of stress. Dynamic oscillatory tests suggest structural changes, with the phase angle following the inverse relationship with the bare cation size, indicating that the liquid-like character of the pulps increases as the size of the cations increases.Minerals 2019, 9, 216 2 of 15 water that surrounds them. Small ions such as Li + are known as maker ions because they attract water molecules more strongly than water molecules do to each other, forming a layer of structured water around the ions. On the other hand, large ions such as Cs + are known as breakers; they interact weakly with water, generating a layer of structureless water around them. This implies that the hydrated size of ions in solution follows the trend Li + > Na + > K + , which is opposite to the bare ion size.More than a century ago, Hofmeister related the precipitation of proteins with the size of bare ions in solution [8]; interestingly, the order established by Hofmeister has been found in various systems, such as colloidal suspensions of tungsten trioxide, magnetite, alumina, titanium, hematite, and silica [9][10][11][12][13]. Here, we focus on silica, which has been studied extensively due to its relevance in numerous industrial applications [14-16]; however, it has not been studied combining rheological and physicochemical results in the presence of a series of alkali metal chloride salts. A particularly important result for our work is that of Franks [9], who measured the zeta potential and yield stress of quartz suspensions in concentrated solutions of monovalent electrolytes, finding that poorly hydrated ions, such as Cs + and K + , have a greater impact in reducing the absolute value of the zeta potential than highly hydrated ions, such as Li + and Na + . Franks found a higher yield stress when the pulp was in the presence of breaker ions, although the results were highly dependent on the pH. A challenge that is not yet fully resolved is that of high isoelectric point minerals, such as alumina, the properties of which follow a trend with the size of ions opposite to silica; for example, maker ions generate stronger alumina networks [17][18][19][20][21]. Parson et al. [19] developed a Poisson...

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A non-linear viscoelastic model for sediments flocculated in the presence of seawater salts

Cited by 15 publications

References 25 publications

Experimental study of the rheology of water–kaolinite suspensions

Experimental study of the rheology of water–kaolinite suspensions

Yield stress dependency on the evolution of bubble populations generated in consolidated soft sediments

Analysis of Silica Pulp Viscoelasticity in Saline Media: The Effect of Cation Size

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